The smell of anxiety

When you are anxious, do you sweat more? You may have noticed a slight increase in sweating, but perhaps you may not have noticed a change in your body odor. However, when you are anxious, your smell changes. And the most interesting thing is that the people around you perceive it, although not consciously. In fact, smell has been one of the most forgotten when referring to studies on anxiety, but now some neuroscientists have set out to solve this oversight.

More anxiety = More sweat

In reality, our body responds differently to anxiety. The usual thing is that your heart rate increases, your pupils dilate and you have problems breathing, which is due to the fact that different hormones, generally known as “stress hormones”, are circulating through your blood and changing your metabolism. This entire system prepares you to react to possible danger.

However, with all of these hormones going around, it’s no wonder that your body plans to get rid of them, whether through urine, vomit, or sweat. Therefore, when you start sweating because you are anxious, what happens is that your body is eliminating those excess hormones. This is also because these hormones stimulate some areas of the brain closely linked to bodily functions, such as the hypothalamus, which, when activated, triggers the functioning of the sweat glands.

Given so many changes at the metabolic level, it is not strange that our smell varies, although we are not always able to perceive it. We distill what some scientists have cataloged as “the smell of anxiety.”

Smelling anxiety changes our behavior

We already know that when we are anxious we release certain hormones through sweat. These are not detectable at a conscious level but they do not go unnoticed by our subconscious. This has been demonstrated by a study carried out at the University of Munich.

These researchers recruited 30 healthy people, who were involved in an economic game in which they could make more conservative or riskier decisions. Interestingly, those who were exposed to the smell of anxious people (a sample collected in a container) took a long time to decide but made the riskiest decisions. In other words, we are able to perceive anxiety through smell and that affects our decisions.

It is worth clarifying that this is not the only study that tells us that we are capable of smelling anxiety. Researchers at Kiel University recruited 28 students who had to smell different aromas while having their brains scanned. Among these aromas were those of students who were anxious as they had to face a very important oral exam and those of people who had undergone intense physical activity.

Surprisingly, the participants noticed no differences in people’s scents but their brains did not indicate the same. Neuroscientists noticed that the smell of anxiety activated areas linked to emotional processing and empathy, such as the insula, the anterior cingulate gyrus, the fusiform gyrus and the prefrontal cortex.

Searching for an explanation for the smell of anxiety

In the past it had already been seen that anxiety, the chemical signals of anxiety and the decision-making process share the same pattern of neuronal activation in the brain, so it would not be unreasonable to think that having an anxious person nearby also determines, to a certain extent, the decisions we make.

Apparently, although we are not able to consciously detect the smell of anxiety, our brain processes it and, in some way, tries to explain it and can even generate a similar experience. And everything happens without us realizing it.

Sources:

Haegler, K. et. Al. (2010) No fear no risk! Human risk behavior is affected by chemosensory anxiety signals. Neuropsychologia; 48(13): 3901-3908.

Prehn-Kristensen, A., et. Al. (2009) Induction of Empathy by the Smell of Anxiety. PLoS ONE; 4 (6).